Cumulative backups

ABSTRACT

In one example, a method for method for backing up data begins when a backup notice is received from a node. In response to the notice, a slot is reserved in an accounting system for storage of a cumulative backup. One or more partial backups are then received and merged with any data present in the slot so as to create or modify a cumulative backup in the slot, where the cumulative backup includes the one or more partial backups and any other data in the slot. Upon receipt of an indication that the cumulative backup is final, the cumulative backup is recorded, and access to the cumulative backup enabled.

FIELD OF THE INVENTION

Embodiments of the present invention generally concern backing up andrestoring data. More particularly, embodiments of the invention relateto systems, hardware, computer-readable media, and methods for backingup data in an efficient manner.

BACKGROUND

Entities often generate and use data that is important in some way totheir operations. This data can include, for example, business data,financial data, and personnel data. If this data were lost orcompromised, the entity may realize significant adverse financial andother consequences. Accordingly, many entities have chosen to back upsome or all of their data so that in the event of a natural disaster,unauthorized access, or other events, the entity can recover any datathat was compromised or lost, and then restore that data to one or morelocations, machines, and/or environments.

While systems, hardware, computer-readable media, and methods forbacking up and/or restoring data provide important functionality to theentity for whose benefit they are employed, the particular manner inwhich they are executed can result in the introduction of certainproblems.

For example, backup processes performed in an environment that includemultiple clients may cause the generation of one, or more, backups foreach of the clients every time the backup process is performed. However,these backups can take a significant amount of storage space,particularly when multiple backup processes are performed over a periodof time that result in the generation of multiple backups for eachclient or other node. This situation becomes even more problematic inenvironments where the backups are maintained in storage for anindefinite period of time. Moreover, these backups occupy storage spacethat could otherwise be used for other purposes. While additionalstorage space can be purchased, the additional storage space may beexpensive, and introduces further maintenance and other costs as well.

Another example of a problem that can arise in connection with backupprocesses that involve multiple clients' attempts to reduce the amountof storage space required for the backup. In particular, the individualbackups created for each client or other node in a group may, in someinstances, be combined in some fashion in an attempt to reduce theamount of storage space ultimately required. However, such an approachdoes not eliminate the requirement to store each of the individualbackups until such time as they can be combined. Moreover, the combinedbackup cannot be created until all of the individual backups have beencreated and stored. Thus, this approach to creating a combined backup soas to reduce storage space requirements can result in relatively longbackup windows that consume system resources which could be used forother purposes.

In light of the foregoing, it would be helpful to reduce the amount ofstorage space required by backups of multiple nodes. As well, it wouldbe desirable to be able to reduce the backup window required by a backupprocess that spans multiple nodes.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to describe the manner in which at least some aspects of thisdisclosure can be obtained, a more particular description will berendered by reference to specific embodiments thereof which areillustrated in the appended drawings. Understanding that these drawingsdepict only example embodiments of the invention and are not thereforeto be considered to be limiting of its scope, embodiments of theinvention will be described and explained with additional specificityand detail through the use of the accompanying drawings, in which:

FIG. 1 is directed to aspects of an example operating environment for atleast some embodiments of the invention;

FIGS. 2-5 disclose aspects of an example backup system configuration andassociated methods;

FIG. 6-9 disclose aspects of an example backup system configuration andassociated methods;

FIG. 10 discloses aspects of an example method for performing acumulative backup process; and

FIG. 11 discloses aspects of an example method for performing a restoreprocess using a cumulative backup.

DETAILED DESCRIPTION OF SOME EXAMPLE EMBODIMENTS

Embodiments of the present invention generally concern backing up andrestoring data. At least some embodiments are employed in clusteredenvironments. More particular example embodiments of the inventionrelate to systems, hardware, computer-readable media and methods forbacking up data in a manner that is relatively efficient in terms of thetime required to perform the backup and/or in terms of the storage spacerequired for the backup.

In at least some embodiments, a backup process is performed that isconcerned with backing up data from one or more sources, such as eachnode of a target group of nodes. Depending upon the circumstances, eachnode in the target group may be backed up either in whole, or in part.

After the nodes have been identified, and the data to be backed up fromeach node has been selected, the backup process can begin. In at leastsome embodiments, the backup process proceeds substantially in parallelwith respect to the nodes of the target group such that the data at eachnode is backed up at substantially the same time as the respective dataof the other nodes is backed up. The backup of each node or itsrespective portion may be referred to herein as a partial backup.

As the partial backups are created at each node, they are stored on theserver and merged together to collectively forma cumulative backup thatoccupies only a single slot in the accounting system of an associatedbackup server. The partial backups are synchronized as they are mergedinto the cumulative backup on the server so as to help ensure that noparts of any partial backup are lost due to race conditions orconflicts. When all of the partial backups have been merged together andthe cumulative backup is complete, the cumulative backup is sealed toprevent further changes.

Although the cumulative backup is stored, the individual partial backupsare not stored as separate entities, except insofar as they areincorporated into the cumulative backup. Thus, this cumulative backupapproach can provide a relative reduction in storage requirementsassociated with a backup process by eliminating the need to store boththe cumulative backup, as well as the individual backups for each node.Correspondingly, the need to reserve respective slots for each partialbackup in the accounting system of the backup server is eliminated.Moreover, the cumulative backup process may proceed relatively morequickly than a backup that requires both creation and storage of partialbackups before a final complete backup can be created.

As may be evident from the preceding discussion, and other disclosureherein, embodiments of the invention may provide various advantages,although it is not necessary, or required, that any particularembodiment(s) provide any particular advantage(s). Moreover, andconsistent with the foregoing statement, embodiments within the scope ofone or more claims may additionally, or alternatively, provide one ormore advantages not specifically enumerated herein. Finally, to theextent that possible advantages are enumerated herein, those may bepresent in one or more embodiments in any combination.

A. Example Operating Environments

In general, embodiments of the invention may include and/or beimplemented in an operating environment that includes a target grouphaving one or more nodes that each include data desired to be backed uptogether in the form of a single unified backup.

One or more applications may be hosted by one or more of the nodes ofthe operating environment, and the applications may generate and/orcause the generation of data that is desired to be backed up andrestored. As used herein, the term data is intended to be construedbroadly and includes, by way of example and not limitation, data blocks,atomic data, objects, files, directories, volumes, and any group of oneor more of the foregoing.

As the nodes in the operating environment may each operate autonomously,and in connection with different respective databases and/or other datastores, cumulative backup applications and methods are employed invarious embodiments. In general, the cumulative backup approach involvesthe use of one or more instances of a cumulative backup application tocreate backups of at least a part of one or more nodes and merging thepartial backups, as they are created, into a cumulative backup. Thecumulative backup is stored at the server, and all users in theoperating environment have access to all the data in the cumulativebackup. The integrity of the individual databases of each node ismaintained because that data has no connection to the backed up data.

In at least some embodiments, a respective instance of the cumulativebackup application is hosted by each node that participates, or may, ina cumulative backup. The instance(s) of the cumulative backupapplication operate in connection with logic at the backup server thatimplements various operations concerning the cumulative backup andpartial backups. For example, the logic at the backup server mayinitiate the backup by communicating with the cumulative backupapplication at each node in a target group, and can also providesynchronization services with regard to the respective partial backupscreated by each instance of the cumulative backup application.

With the foregoing in mind, attention is directed now to FIG. 1 whichdiscloses one example of an operating environment that may be suitablefor one or more embodiments of the invention. In FIG. 1, the exampleoperating environment is denoted at 100 and may be a network such as alocal area network, a wide area network, or any other networkedconfiguration. Moreover, the operating environment 100, or any group ofone or more of its elements, may comprise, form an element of, orconstitute, a cloud computing environment. For example, one or morenodes, discussed below, may comprise elements of a cloud computingenvironment. The environment 100 may include various devices includingservers and other computers that are interconnected. The operatingenvironment 100 may employ a variety of communication media, such ashardwire, wireless, or some combination thereof. In some instances, someor all of the operating environment 100 may comprise an opticalcommunication network.

As indicated in FIG. 1, the example operating environment 100 includes abackup server 200 configured for communication with one or more nodes,such as one or more clients 300. In general, cumulative backups can berestored to the client 300 and/or any other desired machine. The backupserver 200 and client 300 may be physical machines, virtual machines, orany other suitable type of device.

With particular reference first to the backup server 200, someembodiments may employ a backup server 200 in the form of an EMC Avamarserver or EMC NetWorker server, although the scope of the invention isnot limited to those example servers. The backup server 200 includesserver logic 202 that participates in the generation of cumulativebackups. The backup server 200 further includes storage 204 where one ormore cumulative backups can be stored. In addition to the server logic202 and storage 204, the backup server 200 may also include an I/Odevice 206, memory 208, and one or more processors 210. As well, one ormore applications 212 may be provided that comprise executableinstructions.

One or more of the nodes, such as client 300, with which the backupserver 200 communicates can take the form of a server, such as a mailserver, examples of which include a Lotus Notes server, and an MSExchange server. However, it is not required that any server be a mailserver or any other particular type of server. In some embodiments, therelation between two or more nodes may be such that the nodes should bebacked up together. Such groups of nodes include, for example, machinedatabases, MS Exchange servers, and VMWare applications.

One or more of the client(s) 300 include a cumulative backup application302 that generally operates in cooperation with the server logic 202 ofthe backup server 200 to create one or more cumulative backups thatinclude data that is resident on storage media 304, such as disks forexample, of the client 300. A variety of different backup applicationscan be used for the cumulative backup process, and with an associatedrestore process. One example is the EMC Avtar cumulative backupapplication, which is an Avamar Windows backup client. However, otherbackup applications can alternatively be employed in connection with oneor more embodiments of the invention.

B. Cumulative Backup—Single Node

With reference now to FIGS. 2-5, and with continued attention to FIG. 1,details are provided concerning an example system configuration, andassociated cumulative backup operations that can be performed inconnection with that configuration. Except as may be noted elsewhereherein, the operating environment 600 of FIGS. 2-5 may be the same, oridentical, to the operating environment disclosed in FIG. 1 and,accordingly, the discussion of FIG. 1 is applicable as well to FIGS.2-5.

As indicated in FIG. 2, directed in part to the initial creation of acumulative backup, the operating environment 600 may include one or morenodes 602 that each host an instance of a cumulative backup application602 a, such as the EMC Avtar application for example. There is no upperlimit to the number of nodes 602 that can participate in a cumulativebackup, and a cumulative backup can be performed using as few as onenode 602. The node(s) 602, one or more of which may comprise, forexample, a mail server such as an MS Exchange server, or a Lotus Notesserver, communicate with a backup server 604, which can take the form ofan EMC Avamar server. In general, the node(s) 602 that will participatein the cumulative backup, and the data to be included in the partialbackup 610 can both be user specified, such as by way of server logic608 at the backup server, at the node 602, and/or by way of a userinterface (UI) at a management console server (MCS).

The backup server 604 includes an accounting system 606 that has, or isotherwise associated with, a plurality of slots 606 a, 606 b, 606 c . .. 606 n, each of which can be allocated for storage of a backup. In theexample of FIG. 2, slot 606 a (#1) has been allocated but no data hasbeen stored yet in slot 606 a. Allocation of slot 606 a can be performedby the server logic 608 of the backup server 604 at the direction of thecumulative backup application 602 a. The logic for requesting allocationof a slot 606 may form part of the cumulative backup application 602 a,and a slot, when allocated, can serve as a unique identifier for thebackup that is stored there.

At, or about, the same time that the request for allocation of a slot ismade, the cumulative backup application 602 a also indicates to thebackup server 604 that the backup to be stored in the slot is a‘partial’ backup. Among other things, this designation as ‘partial’permits one or more instances of the cumulative backup application 602 ato merge data into the data stored in the allocated slot. In at leastsome embodiments, this marking of the backup in the slot is accomplishedwith the use of a ‘hidden’ flag.

In addition to identifying the backup in the slot as a ‘partial’ backup,the ‘hidden’ flag also ensures that the partial backup will not appearin a list of existing backups at the backup server 604 unless a specialflag is present in the command that that is used to obtain that listing,although certain information about the partial backup may still beaccessed even if the ‘hidden’ flag has been set. Such informationincludes, but is not limited to, Backup ID, Backup Creation Time, andBackup Label. For example, if an inquiry is made using Backup ID as acriterion, the Backup ID of the ‘partial’ backup will appear in the listof results.

It should be noted that any such access is to the cumulative backup as awhole as that cumulative backup exists at the time of access, and not tothe constituent partial backups that have been combined to make up thecumulative backup. This is due to the fact that the cumulative backup,when created, exists as a single unified entity and not as a group ofdiscrete partial backups.

In any event, when the cumulative backup that includes the partialbackup is completed, the ‘hidden’ flag can be reset, by a cumulativebackup application 602 a for example, and the cumulative backup can thenbe viewed without the need for any special flags.

With reference now to FIG. 3, the cumulative backup application 602 a ofnode 602 has generated a backup of node 602 that is then stored aspartial backup 610 in slot 606 a. In general, performing a backup ofnode 602 involves backing up the data of interest, creating the metadatanecessary to describe the data that has been backed up, and theassembling the metadata together with the backed up data. This metadatacan include, for example, final root metadata and other accountinginformation that is to be recorded at the backup server 604 inassociation with the backed up data. The data backup, metadata creation,and assembly are performed by the cumulative backup application 602 a.The assembled partial backup can then be transmitted to the backupserver.

Thus, when received and stored by the backup server 604, the partialbackup 610 is in the form of an assembled partial backup, that is, apartial backup whose data and metadata have been transmitted to, andstored on, the backup server 604, but which has not yet been recorded inthe accounting system 606 as complete. By virtue of its status as anassembled, but as yet unrecorded, partial backup, the partial backup 610is, initially, inaccessible for any operations except recording. Afterboth the existence, and metadata, of the partial backup 610 are mergedinto the cumulative backup, such as by the server logic 608, in the slot606 a, the partial backup 610 may then be accessible via the cumulativebackup for selected operations, examples of which are discussed hereinin connection with the ‘hidden’ flag.

In addition to the foregoing circumstances, flags may be required inother cases as well. For example, where an MCS is employed, the MCS mayalso require a flag for access to the partial backup. If present, theMCS can provide centralized management including scheduling of backups,restore of backups, monitoring and reporting.

In terms of its scope and content, the partial backup 610 may be a fullbackup of node 602 or may be a backup of only part of node 602 and, ingeneral, can be directed to any portion of the data residing at node602. The partial backup 610 forms part of a cumulative backup that hasnot yet been completed. It should be noted that, in general, any backup,such as the partial backup 610, that forms part of a cumulative backupis referred to herein as a partial backup by virtue of its nature aspart of a cumulative backup. This is notwithstanding that in someinstances the partial backup may be a backup of an entire node, or abackup of only a portion of a node. Consistent with the foregoing, acumulative backup may span a single node, or multiple nodes.

As further indicated in FIG. 3, the remaining slots 606 b . . . 606 nremain unallocated and unused. Thus, even though a cumulative backup maybe assembled from multiple constituent parts, those parts are not storedindividually at the backup server 604 and, accordingly, only a singleslot is ever required for the cumulative backup and its constituentparts. That is, the backup server is not required to either individuallystore or retain the constituent parts of a cumulative backup. As aresult, the accounting system 606 may include considerably fewer entriesthan might otherwise be the case. As well, and depending upon thestructure of the accounting system 606, embodiments of the invention canreduce the amount of backup storage space required.

Turning now to FIG. 4, the first partial backup 610 and a second partialbackup 612 are associated with a cumulative backup process, but have notyet been merged together. The request to merge the second partial backup612 with the first partial backup 610, when made, originates with thecumulative backup application 602 a on the node which sent the mostrecent partial backup, node 602 in this case. Although the request tomerge, and the logic for doing so, may originate with the cumulativebackup application 602 a at the node 602, the logic may be executed bythe backup server 200.

As further indicated in FIG. 4, only slot 606 a has been allocated andis in use, notwithstanding that multiple partial backups, namely partialbackup 610 and partial backup 612, have been sent to the backup server600. Correspondingly, slots 606 b . . . 606 n remain unallocated andunused, at least in connection with the cumulative backup process withwhich partial backup 610 and partial backup 612 are associated.

As indicated now in FIG. 5, once two or more partial backups, such aspartial backup 610 and partial backup 612 for example, have been sent tothe backup server 600, the multiple backups can be merged together toform a cumulative backup 614 that includes all the data from both of thepartial backups 610 and 612. While shown in different respectiveFigures, it should be understood that partial backup 610 and partialbackup 612 can be added to slot 606 a at the same time, that is, inparallel with each other, or at substantially the same time. In otherinstances, partial backup 610 and partial backup 612 can be added toslot 606 a in a serial fashion, that is, one before the other.

Likewise, partial backup 610 and partial backup 612 can be mergedtogether immediately, or nearly so, after the partial backup 612 isreceived at the backup server 600. With reference briefly again to FIG.4, it should be noted that while FIG. 4 shows partial backup 610 andpartial backup 612 as existing separately prior to their merger, thepartial backup 610 and partial backup 612 may exist in this separatedstate for only a very short time.

As noted earlier, the incomplete cumulative backup residing in the slot606 a is denoted as ‘partial’ through the use of a ‘hidden’ flag. Onepurpose of this marking is to enable subsequent partial backups to beappended to the data of the recorded, but incomplete, cumulative backup.As well, each partial backup is merged with the preceding partialbackup, if only one exists, to form a cumulative backup that includesthe two partial backups, or if a cumulative backup already exists, thereceived partial backup is merged with the already existing cumulativebackup. That is, and as discussed in more detail elsewhere herein, eachnew partial backup can be merged into the whole and is not separatelystored from the whole, nor does it require the allocation or use of itsown respective slot 606.

As will be apparent from the foregoing discussion, a cumulative backupcan exist in an incomplete state prior to the time that all the partialbackups have been merged together, and in a completed state after allthe partial backups have been merged together and locked. For thepurposes of this disclosure, the term cumulative backup embraces bothstates.

As each partial backup is assembled, the cumulative backup applicationcan synchronize the partial backups before they are merged to helpensure that no parts of any partial backup are lost due to raceconditions or conflicts. In general, synchronization involves a lockingof the Backup ID on the backup server 604 so that the newly assembledpartial backup can be merged into the recorded incomplete cumulativebackup residing in the slot 606 a. This synchronization can be performedby the cumulative backup application 602 a, or by the server logic 608at the direction of the cumulative backup application 602 a. Thisprocess results in the generation of new root metadata, which can thenbe recorded in the slot 606 a. When this recording is completed, therecorded incomplete cumulative backup can then be unlocked for themerger of one or more additional partial backups.

If the partial backup 612 is the final partial backup to be incorporatedin the cumulative backup 614, the partial backup 612 can be designated‘final’ by the cumulative backup application 602 a. This designationindicates not only that further partial backups will not be appended topartial backup 612, but also that the server logic 608 should reset the‘hidden’ flag so as to prevent any further modifications to thecumulative backup 614.

While the preceding discussion of FIGS. 2-5 has considered anarrangement where a cumulative backup is created using multiple partialbackups from a single node, a cumulative backup can also be createdusing data from multiple different sources. Further details concerningthe creation of such a cumulative backup are set forth below.

C. Cumulative Backup—Multiple Nodes

In addition to other aspects disclosed elsewhere herein, another usefulaspect of the cumulative backup approach is that such a backup can becreated using one or more partial backups from each of a plurality ofdifferent data sources. In general, such data sources include, but arenot limited to, any node that can run a cumulative backup applicationand communicate with a backup server. As in the case of a single nodeimplementation, the particular nodes and their respective data involvedin a cumulative backup can be user-specified, or can be determinedautomatically according to predetermined criteria that may beuser-specified.

With attention now to FIGS. 6-9, details are provided concerning anarrangement where a cumulative backup is generated using partial backupsfrom each of a plurality of data sources. As the arrangement of FIGS.6-9 is similar in many respects to that of FIGS. 2-5, only selecteddifferences between the two arrangements are addressed below.

Turning first to FIG. 6, an operating environment 700 may includemultiple nodes 702 that each host an instance of a cumulative backupapplication 702 a, such as the EMC Avtar application for example. Thereis no upper limit to the number of nodes 702 that can participate in acumulative backup. The node 702, one or more of which may comprise, forexample, a mail server such as an MS Exchange server, or a Lotus Notesserver, communicate with a backup server 704, which can take the form ofan EMC Avamar server. In general, the nodes 702 that will participate inthe cumulative backup, and the data to be included in the partialbackups 710 a-710 d can both be user specified, such as by way of serverlogic 708 at the backup server, at the nodes 702, and/or by way of auser interface (UI) at a management console server (MCS).

The backup server 704 includes an accounting system 706 that has, or isotherwise associated with, a plurality of slots 706 a, 706 b, 706 c . .. 706 n, each of which can be allocated for storage of a backup. In theexample of FIG. 6, slot 706 a (#1) has been allocated but no data hasbeen stored yet in slot 706 a. Allocation of slot 706 a can be performedat the request of the cumulative backup application 702 a.

As indicated in FIG. 6, each of the nodes 702 contributes a respectivepartial backup, namely, partial backups 710 b, 710 c, and 710 d. Each ofthe partial backups 710 b, 710 c, and 710 d is appended to therespective preceding partial backup. Turning to FIG. 7, it can be seenthat the client 702 that has created partial backup 710 b has mergedthat partial backup with the partial backup 710 a to form an incompletecumulative backup 711. The other nodes 702 have not yet merged theirrespective partial backups 710 c and 710 d into the incompletecumulative backup 711.

As noted similarly in the discussion of FIGS. 2-5, while FIG. 7 suggestsa sequential merging of partial backups, it should be understood that agroup of partial backups, such as partial backups 710 b, 710 and 710 dfor example, can be merged together either serially, or substantially inparallel. Moreover, and as in the case of the partial backups in FIGS.2-5, each of the partial backups 710 b, 710 and 710 d can be mergedsynchronously as they are assembled. Thus, the arrangement indicated inFIG. 7 is provided for the purposes of illustration and should not beconstrued to limit the scope of the invention in any way. As furtherindicated in FIGS. 6 and 7, the backup server 700 includes server logic708 that synchronizes the partial backups before they are merged to helpensure that no parts of any partial backup are lost due to raceconditions or conflicts.

With reference now to FIGS. 8 and 9, it can be seen in FIG. 8 that allof the partial backups 710 a . . . 710 d have been merged together toform a complete and recorded, but not finalized, cumulative backup 712.In FIG. 9, the cumulative backup 712 is finalized by a separateactivation of the cumulative backup application 702 a. Alternatively,finalization may be implemented by whichever cumulative backupapplication 702 a transmitted the final partial backup for inclusion inthe cumulative backup 712. Where multiple nodes 702 transmit theirrespective partial backups substantially contemporaneously with eachother, any of the associated instances of the cumulative backupapplication 702 a can mark its respective partial backup as ‘final.’ Insome instances, a user can designate which node 702 will designate itsrespective partial backup in this way. In any event, designation of apartial backup as ‘final’ serves to reset the ‘hidden’ flag of thecumulative backup, thus making that cumulative backup visible andaccessible in its entirety, and henceforth no longer modifiable.

D. Example Cumulative Backup Methods

Turning now to FIG. 10, details are provided concerning a method forperforming a cumulative backup, one example of which is denoted at 800.It should be noted that the method 800 can be performed with a singledata source, such as a node, performing multiple partial backups, orwith multiple data sources, each of which performs one or more backups.Moreover, while reference is made in the following discussion to asingle client, it should be understood that unless otherwise noted, theclient processes of the method 800 can be performed by multiple clients,and at substantially the same time as each other.

The method can begin at 802 where a cumulative backup application at anode such as a client transmits a backup notice, such as “begincumulative backup,” to a backup server. At 804, the backup serverreceives the backup notice and allocates a slot for the cumulativebackup in the accounting system of the backup server.

Where multiple clients participate in the method 800, only a single slotis needed since the partial backups of all of the participating clientswill be merged into a single cumulative backup that occupies only asingle slot in the accounting server of the backup system. This requestcan be supplied by any of the clients, the identity of which can bespecified by a user, or determined based on default or other criteria.After the slot has been reserved 804 at the backup server, the backupserver transmits 806 the slot information, such as Backup ID forexample, using the current time as the Creation Time for the cumulativebackup, and at 808 that information is received by the cumulative backupapplication at the client.

One or more partial backups are then created and assembled 810 at theclient and/or one or more other clients. Such a partial backup mayinclude all, or a portion of, data resident at the client and some orall of the backed up data may be deduplicated data, although that is notrequired. Regardless of whether part, or all, of the data at a client isbacked up, the resulting backup is referred to as a partial backupinasmuch as it comprises only part of a cumulative backup. The assembledpartial backup includes, in addition to the client data, metadataconcerning that data. At 812, the assembled partial backup is thentransmitted to the backup server and synchronized. In at least someembodiments, the cumulative backup application synchronizes the partialbackup by locking the Backup ID so that the newly assembled partialbackup can be merged 814 by the cumulative backup application, using thesame Backup ID and Creation Time as at 806, into the recorded incompletecumulative backup that resides in the slot. It should be noted that ifthe partial backup is the first to be created, no merger is required andthe partial backup is stored in the reserved slot.

Next, the recorded metadata associated with the recorded incompletecumulative backup is updated 816 to include the metadata of the newlyassembled partial backup so as to create, for example, new rootmetadata. As part of 816, the new root metadata is then recorded in theaccounting slot in association with the updated incomplete cumulativebackup. This recordation involves overwriting the existing metadata ofthe recorded incomplete cumulative backup with the new root metadata.The incomplete cumulative backup can then be unlocked 818 for the mergerof one or more additional partial backups.

At 820, a check is performed to determine whether or not all of thepartial backups required for the cumulative backup have been assembledand merged. If they have not, the process 800 returns to 810. On theother hand, if all of the partial backups required for the cumulativebackup have been assembled and merged, a final execution of thecumulative backup application marks the cumulative backup in the slot asfinal 822.

The cumulative backup is then recorded 824 at the backup server. Therecording of the cumulative backup includes recording information thatis unique to the cumulative backup, such as the creation time of thecumulative backup and a root metadata reference for the cumulativebackup. Non-unique information can also be associated and stored withthe cumulative backup. In at least some implementations, the backup isstored in a location other than the slot, but a link stored in the slotcan be used to associate the slot with the stored backup. The creationtime and root metadata reference enable the cumulative backupapplication to later read, list and restore the cumulative backup to oneor more target machines, one of which can be the node where thecumulative backup application resides.

After recording of the cumulative backup, the ‘hidden’ flag is reset 826by the backup server, sealing the cumulative backup against any furthermodifications, and making the cumulative backup visible without the needfor any special flags. The method 800 then stops at 828.

E. Example Restore Process

With regard, finally, to FIG. 11, details are disclosed concerningaspects of an example method 900 for performing a restore process usinga cumulative backup. The method 900 can be performed by a backup server,or at the direction of a backup server, or cumulative backup applicationresiding on a node such as a client.

At 902, the restore process is initiated. The initiation can beinitiated based on a user request, a predetermined schedule, theoccurrence or non-occurrence of a particular event, and/or any othercriteria. As well, the request for initiation of the restore process canoriginate with a client, a user, and/or by way of an MCS.

A check is performed at 904 to determine if the cumulative backuptargeted for the restore process has been finalized or not. If thecumulative backup has not been finalized, an access flag for thecumulative backup is accessed 906 to enable performance of the restoreoperation. After the access flag has been accessed, the method 900advances to 908 where the cumulative backup is accessed. If, on theother hand, a determination is made 904 that the cumulative backuptargeted for the restore process has been finalized, the method 900advances to 908 where the cumulative backup is accessed. The cumulativebackup can be accessed based on any suitable criteria including, forexample, slot number, label, Backup ID and/or Creation time.

When the cumulative backup has been accessed 908, the method 900 canadvance to 910 where the cumulative backup is used to restore one ormore target nodes. Examples of such target nodes include one or moreclients, such as servers, that can be physical or virtual machines. Atthe conclusion of a successful restore using the cumulative backup, themethod 900 ends 912.

F. Example Computing Devices and Associated Media

The embodiments disclosed herein may include the use of a specialpurpose or general-purpose computer including various computer hardwareor software modules, as discussed in greater detail below. A computermay include a processor and computer storage media carrying instructionsthat, when executed by the processor and/or caused to be executed by theprocessor, perform any one or more of the methods disclosed herein.

As indicated above, embodiments within the scope of the presentinvention also include computer storage media, which are physical mediafor carrying or having computer-executable instructions or datastructures stored thereon. Such computer storage media can be anyavailable physical media that can be accessed by a general purpose orspecial purpose computer.

By way of example, and not limitation, such computer storage media cancomprise hardware such as solid state disk (SSD), RAM, ROM, EEPROM,CD-ROM, flash memory, phase-change memory (“PCM”), or other optical diskstorage, magnetic disk storage or other magnetic storage devices, or anyother hardware storage devices which can be used to store program codein the form of computer-executable instructions or data structures,which can be accessed and executed by a general-purpose orspecial-purpose computer system to implement the disclosed functionalityof the invention. Combinations of the above should also be includedwithin the scope of computer storage media. As well, such media areexamples of non-transitory storage media, and non-transitory storagemedia also embraces cloud-based storage systems and structures, althoughthe scope of the invention is not limited to these examples ofnon-transitory storage media.

Computer-executable instructions comprise, for example, instructions anddata which cause a general purpose computer, special purpose computer,or special purpose processing device to perform a certain function orgroup of functions. Although the subject matter has been described inlanguage specific to structural features and/or methodological acts, itis to be understood that the subject matter defined in the appendedclaims is not necessarily limited to the specific features or actsdescribed above. Rather, the specific features and acts disclosed hereinare disclosed as example forms of implementing the claims.

As used herein, the term ‘module’ or ‘component’ can refer to softwareobjects or routines that execute on the computing system. The differentcomponents, modules, engines, and services described herein may beimplemented as objects or processes that execute on the computingsystem, for example, as separate threads. While the system and methodsdescribed herein can be implemented in software, implementations inhardware or a combination of software and hardware are also possible andcontemplated. In the present disclosure, a ‘computing entity’ may be anycomputing system as previously defined herein, or any module orcombination of modules running on a computing system.

In at least some instances, a hardware processor is provided that isoperable to carry out executable instructions for performing a method orprocess, such as the methods and processes disclosed herein. Thehardware processor may or may not comprise an element of other hardware,such as the computing devices and systems disclosed herein.

In terms of computing environments, embodiments of the invention can beperformed in client-server environments, whether network or localenvironments, or in any other suitable environment. Suitable operatingenvironments for at least some embodiments of the invention includecloud computing environments where one or more of a client, server, ortarget virtual machine may reside and operate in a cloud environment.

The present invention may be embodied in other specific forms withoutdeparting from its spirit or essential characteristics. The describedembodiments are to be considered in all respects only as illustrativeand not restrictive. The scope of the invention is, therefore, indicatedby the appended claims rather than by the foregoing description. Allchanges which come within the meaning and range of equivalency of theclaims are to be embraced within their scope.

What is claimed is:
 1. A method for backing up data, the methodcomprising: receiving a backup notice from a first node; responding tothe backup notice by reserving a slot in an accounting system;transmitting, to the first node, a confirmation that the slot has beenreserved; receiving, from the first node, a first partial backup forstorage in the slot; receiving a second partial backup from a secondnode that is different from the first node, and the first partial backupand the second partial backup comprise data generated, respectively, atthe first and second nodes; merging the first partial backup and thesecond partial backup with any data present in the slot so as to createor modify a cumulative backup in the slot, and the cumulative backupincludes the first partial backup and any other data in the slot;receiving an indication that the cumulative backup is final; recordingthe cumulative backup; and enabling access to the cumulative backup. 2.The method as recited in claim 1, wherein the second partial backup isreceived at the same time as the first partial backup or at a differenttime than the first partial backup.
 3. The method as recited in claim 1,wherein the merger of the first partial backup and a merger of thesecond partial backup are performed at the same time or at differentrespective times.
 4. The method as recited in claim 1, wherein the slotis the only slot in the accounting system that is employed for thestorage of the first partial backup, the final partial backup, and thecumulative backup.
 5. The method as recited in claim 1, wherein: data inthe slot has been locked prior to merging of the first partial backupwith that data; and the cumulative backup in the slot is unlocked afterthe merger is complete and the cumulative backup has been recorded.
 6. Anon-transitory storage medium having stored therein computer executableinstructions which, when executed by one or more hardware processors,perform the operations: receiving a backup notice from a first node;responding to the backup notice by reserving a slot in an accountingsystem; transmitting, to the first node, a confirmation that the slothas been reserved; receiving, from the first node, a first partialbackup for storage in the slot; receiving a second partial backup from asecond node that is different from the first node, and the first partialbackup and the second partial backup comprise data generated,respectively, at the first and second nodes; merging the first partialbackup and the second partial backup with any data present in the slotso as to create or modify a cumulative backup in the slot, and thecumulative backup includes the first partial backup and any other datain the slot; receiving an indication that the cumulative backup isfinal; recording the cumulative backup; and enabling access to thecumulative backup.
 7. The non-transitory storage medium as recited inclaim 6, wherein the second partial backup is received at the same timeas the first partial backup or at a different time than the firstpartial backup, and wherein the merger of the first partial backup and amerger of the second partial backup are performed at the same time or atdifferent respective times.
 8. The non-transitory storage medium asrecited in claim 6, wherein the slot is the only slot in the accountingsystem that is employed for the storage of the first partial backup, thefinal partial backup, and the cumulative backup.
 9. The non-transitorystorage medium as recited in claim 6, wherein: data in the slot has beenlocked prior to merging of the first partial backup with that data; andthe cumulative backup in the slot is unlocked after the merger iscomplete and the cumulative backup has been recorded.
 10. Thenon-transitory storage medium as recited in claim 6, further comprisingmarking the cumulative backup stored in the slot with a ‘hidden’ flag.11. A physical backup server, wherein the physical backup servercomprises: one or more hardware processors; and the non-transitorystorage medium and computer-executable instructions of claim
 6. 12. Anon-transitory storage medium having stored therein computer-executableinstructions which, when executed by one or more hardware processors,perform the following operations: prior to creating a partial backup,transmitting a backup notice from a client to a backup server indicatingthat a cumulative backup is to be performed; receiving, by the clientfrom the backup server, a confirmation that the backup server hasreserved a slot for storage of the cumulative backup; creating andassembling a partial backup that includes both data and metadata;preparing the partial backup for merger with another partial backup thathas been stored in the reserved slot at the backup server bytransmitting and synchronizing the partial backup; requesting merger ofthe partial backup and the another partial backup; determining whetherall parts of the cumulative backup have been assembled and merged; andmarking the cumulative backup as final when all the parts of thecumulative backup have been assembled and merged.
 13. The non-transitorystorage medium as recited in claim 12, wherein synchronizing the firstpartial backup comprises locking a slot of a backup server accountingsystem so that data in the slot cannot be modified.
 14. A physicalclient node, wherein the physical client nodes comprises: one or morehardware processors; and the non-transitory storage medium andcomputer-executable instructions of claim 12.